High voltage electrode for electric dual layer capacitor and method of manufacturing the same

ABSTRACT

A high voltage electrode includes a through type aluminum sheet, a plurality of first hollow protrusion members protruded to one side of the through type aluminum sheet, a plurality of second hollow protrusion members protruded to the other side of the through type aluminum sheet, a metal oxidation layer coated on the through type aluminum sheet, the plurality of first hollow protrusion members, and the plurality of second hollow protrusion members, a first active material sheet bonded to the metal oxidation layer so that it is placed in the first surface of the through type aluminum sheet, and a second active material sheet bonded to the metal oxidation layer so that it is placed in the second surface of the through type aluminum sheet.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No.10-2014-0057835, filed on May 14, 2014 and Korean Patent Application No.10-2015-0018627, filed on Feb. 6, 2015 in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a high voltage electrode for anelectric double layer capacitor and a method of manufacturing the sameand, more particularly, to a high voltage electrode for an electricdouble layer capacitor and a method of manufacturing the same, which arecapable of implementing a high voltage electrode by preventing a loss ofthe surface area of an aluminum sheet that is used in an electrode foran electric double layer capacitor so that a contact area between thealuminum sheet and an active material sheet is increased when forming aplurality of through holes in the aluminum sheet and by forming a metaloxidation layer on the entire surface of the aluminum sheet.

2. Description of the Related Art

An electric double layer capacitor (EDLC) has a less influence on thelifespan although it is repeatedly charged and discharged because itstores electric energy using a physical adsorption phenomenon withreversibility and is being applied to smart phones, hybrid vehicles,electric vehicles, and the energy storage device field applied to solarcell generation. The electric double layer capacitor has an excellentpower density, but has a low energy density. Accordingly, there is aneed to develop materials for electrodes in order to improve the lowenergy density problem.

Korean Patent No. 1166148 (Patent Document 1) relates to a method ofmanufacturing an aluminum current collector having a three-dimensionalpattern structure using photolithography. In the method of manufacturingthe aluminum current collector disclosed in Patent Document 1, first,after an aluminum foil current collector is washed, it is dried usingnitrogen atmosphere. Thereafter, a photoresist solution is coated on asurface of the dried aluminum foil current collector and then dried andcured so that the photoresist solution is selectively exposed.

Thereafter, the photoresist solution that has not been exposed isselectively removed by scattering a developer on the aluminum currentcollector that has been exposed so that the remaining photoresistsolution is fully cured, thereby forming a pattern on the aluminumcurrent collector. The aluminum foil current collector in which thepattern has been formed is placed between two carbon plates, that is,opposite electrodes, AC power is applied to the aluminum foil currentcollector, and primary etching is performed on the aluminum currentcollector in an electrolyte.

Thereafter, the etched aluminum current collector is dried. Next, thealuminum current collector dried after the primary etching is placedbetween the two carbon plates, that is, opposite electrodes, andsecondary etching is performed on the aluminum current collector.Thereafter, the aluminum foil subjected to the secondary etching iswashed and dried.

As in Patent Document 1, the energy density of a conventional electrodefor an electric double layer capacitor is improved by forming a pattern,that is, a plurality of through holes, in an aluminum current collectorusing a photolithography process so that a contact area between thealuminum current collector and active materials is increased.

If a plurality of through holes is formed in an aluminum currentcollector that is used in a conventional electrode for an electricdouble layer capacitor as in Patent Document 1, however, there is aproblem in that the surface area of the aluminum current collector islost by an area that belongs to a total area of the aluminum currentcollector and that is occupied by the through holes.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made keeping in mind theabove problems occurring in the prior art, and an object of the presentinvention is to provide a high voltage electrode for an electric doublelayer capacitor and a method of manufacturing the same, which arecapable of implementing a high voltage electrode by preventing a loss ofthe surface area of an aluminum sheet that is used in an electrode foran electric double layer capacitor so that a contact area between thealuminum sheet and an active material sheet is increased when forming aplurality of through holes in the aluminum sheet and by forming a metaloxidation layer on the entire surface of the aluminum sheet.

In an embodiment, a high voltage electrode for an electric double layercapacitor may include a through type aluminum sheet configured to have aplurality of through holes formed in the through type aluminum sheet sothat the through holes are spaced apart from one another; a plurality offirst hollow protrusion members extended from the through type aluminumsheet in such a way as to communicate with the through holes andprotruded to one side of the through type aluminum sheet; a plurality ofsecond hollow protrusion members spaced apart from the plurality offirst hollow protrusion members, extended from the through type aluminumsheet in such a way as to communicate with the through holes, andprotruded to the other side of the through type aluminum sheet; a metaloxidation layer coated on the through type aluminum sheet, the pluralityof first hollow protrusion members, and the plurality of second hollowprotrusion members; a first active material sheet placed on the firstsurface of the through type aluminum sheet and bonded to the metaloxidation layer so that the plurality of first hollow protrusion membersis buried; and a second active material sheet configured to have theplurality of second hollow protrusion members buried in the secondactive material sheet and placed on the second surface of the throughtype aluminum sheet and bonded to the metal oxidation layer so that thesecond active material sheet is connected to the first active materialsheet through the plurality of first hollow protrusion members and theplurality of second hollow protrusion members.

In an embodiment, a method of manufacturing a high voltage electrode foran electric double layer capacitor may include preparing a through typealuminum sheet configured to have a plurality of first hollow protrusionmembers and a plurality of second hollow protrusion members respectivelyformed in the first surface and second surface of the through typealuminum sheet and to have a metal oxidization layer formed on theentire surface of the through type aluminum sheet by winding the throughtype aluminum sheet on a first roller; preparing a first active materialsheet by winding the first active material sheet on a second roller;preparing a second active material sheet by winding the second activematerial sheet on a third roller; placing the first active materialsheet on the first surface of the through type aluminum sheet and thesecond active material sheet on the second surface of the through typealuminum sheet and transferring the through type aluminum sheet and thefirst active material sheet and the second active material sheet to apress unit; and placing the first active material sheet and the secondactive material sheet in the first surface and second surface of thethrough type aluminum sheet, respectively, bonding the first activematerial sheet and the second active material sheet to the metaloxidation layer, and simultaneously pressurizing the first activematerial sheet and the second active material sheet using the press unitso that the first active material sheet and the second active materialsheet are connected through the plurality of first hollow protrusionmembers and the plurality of second hollow protrusion members.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects of the present invention will becomeapparent and more readily appreciated from the following description ofthe exemplary embodiments, taken in conjunction with the accompanyingdrawings in which:

FIG. 1 is a cross-sectional view of a high voltage electrode which maybe applied to an electric double layer capacitor in accordance with anembodiment of the present invention;

FIG. 2 is a cross-sectional view illustrating a state before an activematerial sheet is bonded to a through type aluminum sheet of FIG. 1;

FIG. 3 is a rear view of the through type aluminum sheet of FIG. 2 whichis seen from the other side;

FIG. 4 is a table illustrating various embodiments of first hollowprotrusion members illustrated in FIG. 2;

FIG. 5 is a process flowchart illustrating a method of manufacturing thehigh voltage electrode, which may be applied to an electric double layercapacitor in accordance with an embodiment of the present invention;

FIG. 6 is a table illustrating the characteristics of activated carbonthat is used to manufacture a high density electrode, which may beapplied to an electric double layer capacitor in accordance with anembodiment of the present invention; and

FIG. 7 is a diagram schematically illustrating the configuration of anapparatus for manufacturing the high voltage electrode, which may beapplied to an electric double layer capacitor in accordance with anembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to exemplary embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to the like elementsthroughout. Exemplary embodiments are described below to explain thepresent invention by referring to the figures.

Hereinafter, a high voltage electrode for an electric double layercapacitor and a method of manufacturing the same according to someembodiments of the present invention are described.

As illustrated in FIGS. 1 and 2, the high voltage electrode for anelectric double layer capacitor in accordance with an embodiment of thepresent invention may include a through type aluminum sheet 10, a firstactive material sheet 20, and a second active material sheet 30.

The through type aluminum sheet 10 has a plurality of through holes 11 aand 12 a spaced apart from one another and formed therein and includes aplurality of first hollow protrusion members 11, a plurality of secondhollow protrusion members 12, and a metal oxidation layer 13. Theplurality of first hollow protrusion members 11 is extended from thethrough type aluminum sheet 10 in such a way as to respectivelycommunicate with the plurality of through holes 11 a and is protruded toone side of the through type aluminum sheet 10. The plurality of secondhollow protrusion members 12 is spaced apart from the plurality of firsthollow protrusion members 11. Furthermore, the plurality of secondhollow protrusion members 12 is extended from the through type aluminumsheet 10 in such a way as to respectively communicate with the throughholes 12 a and is protruded to the other side of the through typealuminum sheet 10. The metal oxidation layer 13 is coated on the throughtype aluminum sheet 10, the plurality of first hollow protrusion members11, and the plurality of second hollow protrusion members 12. The firstactive material sheet 20 is placed on the first surface 10 a of thethrough type aluminum sheet 10 and bonded to the metal oxidation layer13 so that the plurality of first hollow protrusion members 11 is buriedin the first active material sheet 20. The second active material sheet30 is placed on the second surface 10 b of the through type aluminumsheet 10 and bonded to the metal oxidation layer 13 so that theplurality of second hollow protrusion members 12 is buried in the secondactive material sheet 30 and the second active material sheet 30 isconnected to the first active material sheet 20 through the plurality offirst hollow protrusion members 11 and the plurality of second hollowprotrusion members 12.

The configuration of the high voltage electrode for an electric doublelayer capacitor in accordance with an embodiment of the presentinvention is described in more detail below.

As illustrated in FIGS. 1 to 3, the through type aluminum sheet 10includes the plurality of through holes 11 a and 12 a spaced apart fromone another. The first surface 10 a and second surface 10 b of thethrough type aluminum sheet 10 are formed to be penetrated. Each of thediameters D1 and D3 of the respective holes 11 a and 12 a may be 50 to 0μm. The through type aluminum sheet 10 in which the plurality of throughholes 11 a and 12 a is formed may have a thickness T1 of 10 to 50 μm.The through type aluminum sheet 10 improves a specific resistancecharacteristic using purity of 99.20 to 99.99%, thereby improving theelectrical properties of the high voltage electrode applied to anelectric double layer capacitor in accordance with an embodiment of thepresent invention. In this case, FIG. 1 is an enlarged sectional view ofa portion “Aa” illustrated in FIG. 7 and the through type aluminum sheet10 of FIG. 2 is a cross-sectional view of line “A-A” illustrated in FIG.3.

As illustrated in FIGS. 2 and 3, the plurality of through holes 11 a and12 a is formed in the through type aluminum sheet 10 by perforating thethrough type aluminum sheet 10 using one of a cylindrical pillar member(not illustrated), an elliptical pillar member (not illustrated), and asquare pillar member (not illustrated) each having a pointed tip, suchas a needle or a drill, by applying pressure on the part of the firstsurface 10 a or the second surface 10 b. The plurality of first hollowprotrusion members 11 and the plurality of second hollow protrusionmembers 12 are extended from the through type aluminum sheet 10 andprotruded so that they respectively communicate with the plurality ofthrough holes 11 a and 12 a. As illustrated in FIG. 4, each of theplurality of through holes 11 a and 12 a may have one of a cylindricalshape, an oval, and a square shape and may be formed as one of thecylindrical pillar member, the elliptical pillar member, and the squarepillar member. FIG. 4 is a table illustrating various embodiments of thefirst hollow protrusion member 11. The second hollow protrusion member12 is applied like the first hollow protrusion members 11 of FIG. 4, andthus a description and drawings of various embodiments of the secondhollow protrusion members 12 are omitted.

For example, the plurality of first hollow protrusion members 11 mayinclude the plurality of through holes 11 a formed in the through typealuminum sheet 10 by perforating one of the cylindrical pillar member,the elliptical pillar member, and the square pillar member having apoint end in the direction toward the first surface 10 a of the throughtype aluminum sheet 10 by applying pressure. The plurality of firsthollow protrusion members 11 is extended from the through holes 11 a bythe softness of the through type aluminum sheet 10 and protruded to oneside of the through type aluminum sheet 10. In this case, the throughhole 11 a may have one of a cylindrical shape, an oval, and a squareshape because it is formed of one of the cylindrical pillar member, theelliptical pillar member, and the square pillar member, as illustratedin FIG. 4.

Each of the plurality of through holes 11 a may have one of acylindrical shape, an oval, and a square shape because it is formed ofthe cylindrical pillar member, the elliptical pillar member, and thesquare pillar member, as illustrated in FIG. 4. For example, if thecylindrical pillar member is used, each of the plurality of throughholes 11 a may have a cylindrical shape as in a column Y1. If theelliptical pillar member is used, each of the plurality of through holes11 a may have an oval as in a column Y3. If the square pillar member isused, each of the plurality of through holes 11 a may have a squareshape as in a column Y2. The first hollow protrusion members 11illustrated in a row X3 are perspective views of the first hollowprotrusion members 11 illustrated in a row X2.

The plurality of through holes 12 a of the plurality of second hollowprotrusion members 12 is formed in the through type aluminum sheet 10 byperforating the through type aluminum sheet 10 in the direction towardthe second surface 10 b of the through type aluminum sheet 10 byapplying pressure using one of the cylindrical pillar member, theelliptical pillar member, and the square pillar member each having apointed tip. The plurality of second hollow protrusion members 12 isextended from the through holes 11 a by the softness of the through typealuminum sheet 10 and protruded to the other side of the through typealuminum sheet 10. In this case, like the plurality of through holes 11a of FIG. 4, each of the plurality of through holes 12 a has one of acylindrical shape, an oval, and a square shape because it is formed ofone of the cylindrical pillar member, the elliptical pillar member, andthe square pillar member, as illustrated in FIG. 4.

The plurality of first hollow protrusion members 11 and the plurality ofsecond hollow protrusion members 12 include one or more extruded burrmembers 11 b, 11 c, and 11 d and 12 b, 12 c, and 12 d because they aremade of one of the cylindrical pillar member, the elliptical pillarmember, and the square pillar member each having a pointed tip. Forexample, as illustrated in FIG. 3, the first hollow protrusion member 11and the second hollow protrusion member 12 may include respectiveextruded burr members 11 b and 12 b or may have two or more extrudedburr members 11 b, 11 c, and 11 d and 12 b, 12 c, and 12 d. That is, asingle through type aluminum sheet 10 may include the first hollowprotrusion member 11 and the second hollow protrusion member 12 thatinclude respective extruded burr members 11 b and 12 b or include thetwo or more extruded burr members 11 b, 11 c, and 11 d and 12 b, 12 c,and 12 d, respectively. As in the first hollow protrusion members 11 ofFIG. 4, the first hollow protrusion member 11 may include four extrudedburr members 11 b, 11 c, 11 d, and 11 e if the through hole 11 a isformed to have a square shape or an oval as in the column Y3 or thecolumn Y3. The same principle applied to the first hollow protrusionmembers 11 may be applied to the second hollow protrusion members 12. Inthe table of FIG. 4, the row X1 illustrates an embodiment in which twoextruded burr members 11 b and 11 c have been formed in the first hollowprotrusion member 11. The row X2 illustrates an embodiment in whichthree or four extruded burr members 11 b, 11 c, 11 d, and 11 e have beenformed in the first hollow protrusion member 11. The row X3 is aperspective view of the first hollow protrusion member 11 illustrated inthe row X1. Furthermore, FIG. 1 is a cross-sectional view of a highvoltage electrode for an electric double layer capacitor formed thefirst hollow protrusion members 11 and the second hollow protrusionmembers 12 in which the two extruded burr members 11 b, 11 c, and 12 b,12 c illustrated in the row X1 and column Y1 of FIG. 4 have been formed.

The one or more extruded burr members 11 b, 11 c, and 11 d and 12 b, 12c, and 12 d are extended from the through holes 11 a and 12 a and areintegrally formed in the through type aluminum sheet 10 so that they arespaced apart from one another. The one or more extruded burr members 11b, 11 c, and 11 d and 12 b, 12 c, and 12 d have respective heights T2and T3 of 2 to 70 μm. For example, as illustrated in FIGS. 2 and 4, theheights T2 and T3 of the extruded burr members 11 b and 12 b are thehighest heights from the first surface 10 a of the through type aluminumsheet 10 or the second surface 10 b. The plurality of extruded burrmembers 11 b, 11 c, and 11 d and 12 b, 12 c, and 12 d has beenillustrated as having a height of 2 μm or more from the first surface 10a of the through type aluminum sheet 10 or the second surface 10 b inthe state in which they have been separated. Since the plurality offirst hollow protrusion members 11 and the plurality of second hollowprotrusion members 12 are formed to have the one or more extruded burrmembers 11 b, 11 c, and 11 d and 12 b, 12 c, and 12 d as describedabove, thereby further increasing the surface area of the through typealuminum sheet 10. For example, if the first hollow protrusion member 11and the second hollow protrusion member 12 are formed of cylindricalpillar members, the cylindrical through holes 11 a and 12 a havinguniform diameters D1 and D3 may be formed in the first hollow protrusionmember 11 and the second hollow protrusion member 12, or the extrudedburr members 11 b and 12 b may be formed so that one side or the otherside of the first hollow protrusion member 11 and the second hollowprotrusion member 12 has an inside diameter D2, D4 equal to or smallerthan the diameter D1, D3. Accordingly, the surface area of the throughtype aluminum sheet 10 can be further increased.

The metal oxidation layer 13 is coated on surfaces of the through typealuminum sheet 10, the plurality of first hollow protrusion members 11,and the plurality of second hollow protrusion members 12 and configuredto surround the through type aluminum sheet 10. That is, the metaloxidation layer 13 is configured to include a surface of the throughtype aluminum sheet 10, the outer circumference surface and innercircumference surface of the plurality of first hollow protrusionmembers 11, and the outer circumference surface and inner circumferencesurface of the plurality of second hollow protrusion members 12.Accordingly, an electric double layer capacitor to which an electrode inaccordance with an embodiment of the present invention has been appliedcan implement a high voltage. In this case, Al₂O₃ may be used asmaterials for the metal oxidation layer 13. The metal oxidation layer 13is formed on the entire surface of the through type aluminum sheet 10,including the plurality of first hollow protrusion members 11 and theplurality of second hollow protrusion members 12, using an anodizationmethod.

As illustrated in FIGS. 1 and 2, the first active material sheet 20 andthe second active material sheet 30 are simultaneously pressurized tothe first surface 10 a and second surface 10 b of the through typealuminum sheet 10 and bonded to the metal oxidation layer 13 byrepeating a roll press method twice or more so that they are connectedthrough the plurality of first hollow protrusion members 11 and theplurality of second hollow protrusion members 12. If the roll pressmethod is repeatedly performed twice or more, the thicknesses T4 and T5of the first active material sheet 20 and the second active materialsheet 30 pressurized by the roll press method that is finally performedare 2 to 30% smaller than the thicknesses T6 and T7 (refer to FIG. 7) ofthe first active material sheet 20 and the second active material sheet30 pressurized by the roll press method that is first performed.

As described above, the first active material sheet 20 and the secondactive material sheet 30 are simultaneously pressurized and bonded tothe through type aluminum sheet 10 by repeating the roll press methodtwice or more. Accordingly, external appearances of the plurality offirst hollow protrusion members 11 and the plurality of second hollowprotrusion members 12 can be prevented from being changed or damage tothe through holes 11 a and 12 a, such as that the through holes 11 a and12 a are clogged, can be prevented due to applied pressure for bondingthe first active material sheet 20 and the second active material sheet30 together, and an equivalent series resistance characteristic can beprevented from being deteriorated, thereby being capable of implementingan electrode with a high voltage.

For example, the high voltage electrode for an electric double layercapacitor in accordance with an embodiment of the present invention maybe formed by repeating a roll press method twice or more using a pressunit 140 illustrated in FIG. 7.

In the roll press method that is first performed, the first activematerial sheet 20 and the second active material sheet 30 are bonded tothe metal oxidation layer 13 so that they are respectively placed on thefirst surface 10 a and second surface 10 b of the through type aluminumsheet 10 by applying pressure lower than that used in the roll pressmethod that is finally performed. That is, since the first activematerial sheet 20 and the second active material sheet 30 are bonded tothe through type aluminum sheet 10 with low pressure, a change inexternal appearances of the plurality of first hollow protrusion members11 and the plurality of second hollow protrusion members 12 attributableto the pressure can be prevented. As described above, in the roll pressmethod that is first performed, the first active material sheet 20 andthe second active material sheet 30 are partially filled in the firsthollow protrusion members 11 or the second hollow protrusion members 12.As a result, a change in external appearances of the first hollowprotrusion members 11 or the second hollow protrusion members 12, whichmay occur because pressure higher than the pressure used in the rollpress method that is first performed is applied to the first hollowprotrusion members 11 or the second hollow protrusion members 12, can beprevented.

If the roll press method that is second performed is a roll press methodthat is finally performed, in the roll press method that is finallyperformed, the first active material sheet 20 and the second activematerial sheet 30 are bonded to the metal oxidation layer 13 so thatthey are respectively placed on the first surface 10 a and secondsurface 10 b of the through type aluminum sheet 10 by applying pressurehigher than that used in the roll press method that is first performed.In the roll press method that is finally performed, although pressurehigher than that used in the roll press method that is first performedis applied, external appearances of the first hollow protrusion members11 or the second hollow protrusion members 12 can be prevented frombeing changed because the first active material sheet 20 and the secondactive material sheet 30 have been partially filled in the first hollowprotrusion members 11 or the second hollow protrusion members 12 to someextent. In the roll press method that is finally performed, the firstactive material sheet 20 and the second active material sheet 30 aresimultaneously pressurized by applying pressure higher than that used inthe roll press method that is first performed. Accordingly, the firstactive material sheet 20 and the second active material sheet 30 arefilled in the plurality of through holes 11 a and 12 a in the state inwhich they have been filled in the plurality of first hollow protrusionmembers 11 and the plurality of second hollow protrusion members 12 andare thus connected.

By the roll press method that is finally performed, the first activematerial sheet 20 and the second active material sheet 30 are filled inthe plurality of through holes 11 a and 12 a in the state in which theyhave been filled in the plurality of first hollow protrusion members 11and the plurality of second hollow protrusion members 12 and bonded tothe inner circumference surfaces or outer circumference surfaces of theplurality of first hollow protrusion members 11 and the plurality ofsecond hollow protrusion members 12. Accordingly, the deterioration ofan equivalent series resistance characteristic can be prevented becausea contact area between the through type aluminum sheet 10 and the firstactive material sheet 20 and the second active material sheet 30 isincreased. The first active material sheet 20 and the second activematerial sheet 30 are made of the same active materials and are formedby pressurization so that they have the thicknesses T4 and T5 reduced by2 to 30% compared to the thicknesses T6 and T7. Accordingly, a highvoltage electrode having an improved series resistance characteristiccan be fabricated because a contact area is increased, and each of thethicknesses T4 and T5 may be 100 to 500 μm. In this case, activatedcarbon may be used as the active materials, and activated carbon mayhave an average particle diameter of about 1 to 10 μm and a specificsurface area of 1200 to 2200 m²/g.

A method of manufacturing the high voltage electrode for an electricdouble layer capacitor in accordance with an embodiment of the presentinvention is described below with reference to the accompanyingdrawings.

In the method of manufacturing the high voltage electrode for anelectric double layer capacitor in accordance with an embodiment of thepresent invention, as illustrated in FIGS. 5 and 7, first, the throughtype aluminum sheet 10 in which the plurality of first hollow protrusionmembers 11 and the plurality of second hollow protrusion members 12 havebeen respectively formed in the first surface 10 a and second surface 10b of the through type aluminum sheet 10 and the metal oxidation layer 13has been formed on the entire surface of the through type aluminum sheet10 is prepared by winding the through type aluminum sheet 10 on a firstroller 110 at step S10. Furthermore, the first active material sheet 20is prepared by winding the first active material sheet 20 on a secondroller 120 at step S20, and the second active material sheet 30 isprepared by winding the second active material sheet 30 on a thirdroller 130 at step S30. When the first roller 110, the second roller120, and the third roller 130 are prepared, the first active materialsheet 20 is placed on the first surface 10 a of the through typealuminum sheet 10, the second active material sheet 30 is placed on thesecond surface 10 b of the through type aluminum sheet 10, and thethrough type aluminum sheet 10, the first active material sheet 20, andthe second active material sheet 30 are transferred to the press unit140 at step S40. When the through type aluminum sheet 10, the firstactive material sheet 20, and the second active material sheet 30 aretransferred to the press unit 140, the first active material sheet 20and the second active material sheet 30 are simultaneously pressurizedby the press unit 140 so that they are respectively placed on the firstsurface 10 a and second surface 10 b of the through type aluminum sheet10 and bonded to the metal oxidation layer 13 and they are connectedthrough the plurality of first hollow protrusion members 11 and theplurality of second hollow protrusion members 12 at step S50.Thereafter, the high voltage electrode for an electric double layercapacitor in accordance with an embodiment of the present invention isfabricated using a known dry process.

At step S10 of preparing the through type aluminum sheet 10 by windingit on the first roller 110, first, the plurality of first hollowprotrusion members 11 and the plurality of second hollow protrusionmembers 12 are respectively formed on the first surface 10 a and secondsurface 10 b of the through type aluminum sheet 10 at step S11. That is,the plurality of first hollow protrusion members 11 and the plurality ofsecond hollow protrusion members 12 are integrally formed in the throughtype aluminum sheet 10 so that they are extended from the through typealuminum sheet 10 and protruded in such a way as to communicate with theplurality of through holes 11 a and 12 a by perforating the through typealuminum sheet 10 using one of the cylindrical pillar member (notillustrated), the elliptical pillar member (not illustrated), and thesquare pillar member (not illustrated) each having a pointed tip byapplying pressure to the first surface 10 a or the second surface 10 bof the through type aluminum sheet 10 so that the plurality of throughholes 11 a and 12 a is formed in the through type aluminum sheet 10.

The plurality of first hollow protrusion members 11 and the plurality ofsecond hollow protrusion members 12 formed in the through type aluminumsheet 10 are protruded to one side or the other side of the through typealuminum sheet 10, that is, in a first direction or a second direction.The first direction is a direction toward the first surface 10 a of thethrough type aluminum sheet 10. The second direction is opposite thefirst direction and is a direction toward the second surface 10 b of thethrough type aluminum sheet 10.

When the plurality of first hollow protrusion members 11 and theplurality of second hollow protrusion members 12 are formed, the metaloxidation layer 13 is formed by anodizing the through type aluminumsheet 10 in which the plurality of first hollow protrusion members 11and the plurality of second hollow protrusion members 12 have beenformed. After the metal oxidation layer 13 is formed, the through typealuminum sheet 10 is prepared by winding it on the first roller 110 atstep S12. In this case, the metal oxidation layer 13 is formed using ananodization method, and Al₂O₃ is used as materials for the metaloxidation layer 13 formed by the anodization method.

At step S20 of preparing the first active material sheet 20 by windingit on the second roller 120 and step S30 of preparing the second activematerial sheet 30 by winding it on the third roller 130, the firstactive material sheet 20 and the second active material sheet 30 aremade of the same active materials. The active materials may include anelectrode substance of 60 to 80 wt % and a viscosity control substanceof 20 to 40 wt % and may have viscosity of 5000 to 10000 cps (centiPoise). The first active material sheet 20 and the second activematerial sheet 30 having some degree of viscosity as described above aretransferred and bonded to the through type aluminum sheet 10, therebybeing capable of improving adhesive strength between the first activematerial sheet 20 and the second active material sheet 30. In this case,the electrode substance may include activated carbon of 85 to 95 wt %, aconductive agent of 3 to 8 wt %, and a binder of 2 to 7 wt %. Theviscosity control substance may include alcohol of 30 to 60 wt % andpure water of 40 to 70 wt %. Activated carbon is manufactured byperforming activation processing on carbon particle powder fabricatedusing a known aqueous solution method. The activation processing isperformed by mixing the carbon particle powder and mixed alkali in a wt% ratio of 1:2 to 3, drying the mixture, and performing annealing on themixture in a tube furnace under a nitrogen atmosphere in a temperatureof 600 to 1000° C. The mixed alkali is mixed so that a wt % ratio ofNaOH and KOH is 1:9 to 12.

A method of manufacturing activated carbon is described in detail below.First, carbon particle powder is fabricated using a known aqueoussolution method. Known raw materials may be used as the carbon particlepowder. Pitch coke, coconut peels, or a bio substance may be used as theraw materials. Potato starch or corn may be used as the bio substance.After the carbon particle powder is fabricated, activation processing isperformed on the carbon particle powder. In the activation processing,first, the carbon particle powder is immersed in a mixed alkali solutionfor 30 minutes to 2 hours, and the carbon particle powder and mixedalkali are mixed by agitating them for 10 to 15 hours.

After the carbon particle powder is mixed with mixed alkali, the mixtureis filtered using a known filter and dried in vacuum in a temperature of100 to 130° C. for 10 to 15 hours. Thereafter, the mixture is activatedby performing annealing in a tube furnace under a nitrogen atmosphere ina temperature of 600 to 1000° C. for 30 minutes to 1½ hours. When theactivation is completed, the carbon particle powder mixed with mixedalkali is repeatedly washed using distilled water once to 10 times anddried, thereby fabricating activated carbon.

When fabricating activated carbon, mixed alkali including NaOH and KOHforms pores having two types of sizes according to NaOH and KOH inactivated carbon. That is, K ions and Na ions form pores of differentsizes in activated carbon because they have different sizes anddifferent activation operations. For example, K ions may form pores thatare narrower and deeper than pores formed by the activation of Na. Naions may form pores that are wider and smaller than pores formed by theactivation of K ions.

As illustrated in FIG. 6, the specific surface area of activated carbonwas increased in experiments in which a wt % ratio of carbide and mixedalkali was changed to 1:2, 1:2.3, 1:2.6, and 1:3 in the state in which awt % ratio of NaOH and KOH was fixed to 1:9. If a wt % ratio of KOH isincreased in mixed alkali as in those experimental embodiments, thespecific surface area of activated carbon is increased from 1200 m²/g to2200 m²/g as illustrated in FIG. 6, thereby enabling activated carbonhaving an average particle diameter of 1 to 10 μm to be used. That is,the specific surface area of activated carbon is increased althoughactivated carbon has a small average particle diameter. Accordingly, thefirst active material sheet 20 and the second active material sheet 30having a low equivalent series resistance characteristic can befabricated because a contact area between the activated carbon and themetal oxidation layer 13 is increased.

Metal impurities that remain in activated carbon was reduced by changinga wt % ratio of carbide and mixed alkali into 1:3, 1:2.6, 1:2.3, or 1:2in the state in which the wt % ratio of NaOH and KOH was fixed to 1:9,as illustrated in FIG. 6. For example, there is an advantage in that themetal impurities were improved by the pores formed by Na ions whenwashing activated carbon, as illustrated in FIG. 6. In this case, themetal impurities that remain after washing activated carbon may includeNi and K.

As described above, the specific surface area is increased, but themetal impurities are reduced depending on a ratio of carbide and mixedalkali. However, if an optimal ratio of carbide and mixed alkali isselected depending on the purpose of use of activated carbon, capacityper volume can be increased and the amount of the metal impurities thatremain can be reduced.

At step S50 of simultaneously pressurizing the first active materialsheet 20 and the second active material sheet 30 using the press unit140, as illustrated in FIG. 7, first, when the first active materialsheet 20, the second active material sheet 30, and the through typealuminum sheet 10 are transferred to a pair of first press rollers 141,the first active material sheet 20 and the second active material sheet30 are primarily pressurized using the pair of first press rollers 141with first pressure at the same time so that the first active materialsheet 20 and the second active material sheet 30 are respectively placedon the first surface 10 a and second surface 10 b of the through typealuminum sheet 10 and bonded by the metal oxidation layer 13 at stepS51.

When the through type aluminum sheet 10 onto which the first activematerial sheet 20 and the second active material sheet 30 have primarilypressurized is transferred to a pair of second press rollers 142, thefirst active material sheet 20 and the second active material sheet 30that have been primarily pressurized are secondarily pressurized usingthe pair of second press rollers 142 with second pressure higher thanthe first pressure at the same time so that the first active materialsheet 20 and the second active material sheet 30 are connected throughthe plurality of first hollow protrusion members 11 and the plurality ofsecond hollow protrusion members 12 at step S52. In this case, thepressurization is performed so that the thicknesses T4 and T5 of thefirst active material sheet 20 and the second active material sheet 30bonded to the first surface 10 a and second surface 10 b of the throughtype aluminum sheet 10 by the second pressure are 2 to 30% smaller thanthe thicknesses T6 and T7 (refer to FIG. 7) of the first active materialsheet 20 and the second active material sheet 30 bonded to the firstsurface 10 a and second surface 10 b of the through type aluminum sheet10 by the first pressure.

As illustrated in FIG. 7, the first pressure may be set by an intervalM1, that is, a separation distance between the pair of first pressrollers 141, and the second pressure may be set by an interval M2, thatis, a separation distance between the pair of second press rollers 142.That is, the pair of first press rollers 141 is spaced apart from eachother at the interval M1 so that the first pressure is applied to thefirst active material sheet 20 and the second active material sheet 30,the first active material sheet 20 is formed to a thickness T6, and thesecond active material sheet 30 is formed to a thickness T7.Furthermore, the pair of second press rollers 142 is spaced apart fromeach other at the interval M2 so that the second pressure is applied tothe first active material sheet 20 and the second active material sheet30, the first active material sheet 20 is formed to the thickness T4,and the second active material sheet 30 is formed to the thickness T5.Accordingly, the thicknesses T4 and T5 of the first active materialsheet 20 and the second active material sheet 30 become 2 to 30% smallerthan thicknesses T6 and T7. In this case, the thicknesses T6 and T7 arethe same, and the thicknesses T4 and T5 are also the same.

The thicknesses T4 and T5 of the first active material sheet 20 and thesecond active material sheet 30 that have been secondarily pressurizedso that they are reduced by 2 to 30% compared to the thickness T6 and T7of the first active material sheet 20 and the second active materialsheet 30 that have been primarily pressurized are generated due to adifference M3+M4 between the interval M1 between the pair of first pressrollers 141 and the interval M2 between the pair of second press rollers142. That is, the first pressure and the second pressure are set by theinterval M1 between the pair of first press rollers 141 of the pressunit 140 and the interval M2 between the pair of second press rollers142 of the press unit 140. A difference between the first pressure andthe second pressure is generated due to the difference M3+M4 between theinterval M1 between the pair of first press rollers 141 and the intervalM2 between the pair of second press rollers 142. For example, if theinterval M1 is set to be identical with an interval M2+M3+M4, thethicknesses T4 and T5 of the first active material sheet 20 and thesecond active material sheet 30 may become 2 to 30% smaller than thethicknesses T6 and T7, thereby easily implementing an electrode with ahigh voltage. In this case, the intervals M1 and M2 are respectivelyindicative of the interval between the pair of first press rollers 141spaced apart from each other or the interval between the pair of secondpress rollers 142 spaced apart from each other.

Conductive adhesives are used to further improve adhesive strengthbetween the metal oxidation layer 13 and the first active material sheet20 and the second active material sheet 30. Known materials may be usedas the conductive adhesives. The conductive adhesives are coated on themetal oxidation layer 13 in the spray state so that it is placed on thefirst surface 10 a or second surface 10 b of the through type aluminumsheet 10. After the conductive adhesives are coated on the metaloxidation layer 13, the first active material sheet 20 and the secondactive material sheet 30 are simultaneously pressurized by the pressunit 140 so that the first active material sheet 20 and the secondactive material sheet 30 are more firmly bonded to the metal oxidationlayer 13 through the conductive adhesives. Accordingly, the high voltageelectrode for an electric double layer capacitor in accordance with anembodiment of the present invention is fabricated.

As described above, the high voltage electrode for an electric doublelayer capacitor and the method of manufacturing the same according tothe embodiments of the present invention can implement a high voltageelectrode by preventing a loss of the surface area of an aluminum sheetthat is used in an electrode for an electric double layer capacitor sothat a contact area between the aluminum sheet and the active materialsheet is increased when forming the plurality of through holes in thealuminum sheet and by forming the metal oxidation layer on the entiresurface of the aluminum sheet.

The high voltage electrode for an electric double layer capacitor andthe method of manufacturing the same according to the embodiments of thepresent invention may be applied to the manufacturing industry field forelectric double layer capacitors.

Although a few exemplary embodiments of the present invention have beenshown and described, the present invention is not limited to thedescribed exemplary embodiments. Instead, it would be appreciated bythose skilled in the art that changes may be made to these exemplaryembodiments without departing from the principles and spirit of theinvention, the scope of which is defined by the claims and theirequivalents.

What is claimed is:
 1. A high voltage electrode for an electric doublelayer capacitor, comprising: a through type aluminum sheet configured tohave a plurality of through holes formed in the through type aluminumsheet so that the through holes are spaced apart from one another; aplurality of first hollow protrusion members extended from the throughtype aluminum sheet in such a way as to communicate with the throughholes and protruded to a first side of the through type aluminum sheet;a plurality of second hollow protrusion members spaced apart from theplurality of first hollow protrusion members, extended from the throughtype aluminum sheet in such a way as to communicate with the throughholes, and protruded to a second side of the through type aluminumsheet; a metal oxidation layer coated on the through type aluminumsheet, the plurality of first hollow protrusion members, and theplurality of second hollow protrusion members; a first active materialsheet placed on a first surface of the through type aluminum sheet andbonded to the metal oxidation layer so that the plurality of firsthollow protrusion members is buried; and a second active material sheetconfigured to have the plurality of second hollow protrusion membersburied in the second active material sheet and placed on a secondsurface of the through type aluminum sheet and bonded to the metaloxidation layer so that the second active material sheet is connected tothe first active material sheet through the plurality of first hollowprotrusion members and the plurality of second hollow protrusionmembers, wherein: each of the plurality of first hollow protrusionmembers and the plurality of second hollow protrusion members is formedby perforating the through type aluminum sheet by applying pressure onthe first side or second side of the through type aluminum sheet usingone of a cylindrical pillar member, an elliptical pillar member, and asquare pillar member each having a pointed tip so that the plurality ofthrough holes is formed in the through type aluminum sheet, theplurality of first hollow protrusion members and the plurality of secondhollow protrusion members are extended and protruded from the throughtype aluminum sheet in such a way as to respectively communicate withthe plurality of through holes, and each of the through holes has one ofa cylindrical shape, an oval, and a square shape by one of thecylindrical pillar member, the elliptical pillar member, and the squarepillar member.
 2. The high voltage electrode of claim 1, wherein: theplurality of through holes spaced apart from one another is formed inthe through type aluminum sheet, the first surface and second surface ofthe through type aluminum sheet penetrate the plurality of throughholes, and each of the plurality of through holes has a diameter of 50to 100 μm.
 3. The high voltage electrode of claim 1, wherein the throughtype aluminum sheet has a thickness of 10 to 50 μm.
 4. The high voltageelectrode of claim 1, wherein each of the plurality of first hollowprotrusion members and the plurality of second hollow protrusion memberscomprises one or more extruded burr members formed by one of acylindrical pillar member, an elliptical pillar member, and a squarepillar member each having a pointed tip.
 5. The high voltage electrodeof claim 4, wherein: the one or more extruded burr members are spacedapart from one another and integrally formed in the through typealuminum sheet so that the extruded burr members are extended from thethrough hole, and each of the one or more extruded burr members has aheight of 2 to 70 μm.
 6. The high voltage electrode of claim 1, wherein:the first active material sheet and the second active material sheet aresimultaneously pressurized and bonded the metal oxidation layer so thatthe first active material sheet and the second active material sheet areplaced on the first surface and second side of the through type aluminumsheet by repeating a roll press method twice or more so that the firstactive material sheet and the second active material sheet are connectedthrough the plurality of first hollow protrusion members and theplurality of second hollow protrusion members, and if the roll pressmethod is repeatedly performed twice or more, each of a thickness of thefirst active material sheet and a thickness of the second activematerial sheet pressurized by a roll press method that is finallyperformed is 2 to 30% smaller than each of a thickness of the firstactive material sheet and a thickness of the second active materialsheet pressurized by a roll press method that is first performed.
 7. Thehigh voltage electrode of claim 1, wherein: the first active materialsheet and the second active material sheet are made of identical activematerials, each of the first active material sheet and the second activematerial sheet has a thickness of 100 to 500 μm, the active materialscomprise activated carbon, and the activated carbon has an averageparticle diameter of 1 to 10 μm and a specific surface area of 1200 to2200 m²/g.
 8. A method of manufacturing a high voltage electrode for anelectric double layer capacitor, the method comprising: preparing athrough type aluminum sheet configured to have a plurality of firsthollow protrusion members and a plurality of second hollow protrusionmembers respectively formed in a first surface and second surface of thethrough type aluminum sheet and to have a metal oxidization layer formedon an entire surface of the through type aluminum sheet by winding thethrough type aluminum sheet on a first roller; preparing a first activematerial sheet by winding the first active material sheet on a secondroller; preparing a second active material sheet by winding the secondactive material sheet on a third roller; placing the first activematerial sheet on the first surface of the through type aluminum sheetand the second active material sheet on the second surface of thethrough type aluminum sheet and transferring the through type aluminumsheet and the first active material sheet and the second active materialsheet to a press unit; and placing the first active material sheet andthe second active material sheet in the first surface and second surfaceof the through type aluminum sheet, respectively, bonding the firstactive material sheet and the second active material sheet to the metaloxidation layer, and simultaneously pressurizing the first activematerial sheet and the second active material sheet using the press unitso that the first active material sheet and the second active materialsheet are connected through the plurality of first hollow protrusionmembers and the plurality of second hollow protrusion members, whereinpreparing the through type aluminum sheet by winding the through typealuminum sheet on the first roller comprises: forming the plurality offirst hollow protrusion members and the plurality of second hollowprotrusion members in the first surface and second surface of thethrough type aluminum sheet, respectively; and forming the metaloxidation layer by anodizing the through type aluminum sheet in whichthe plurality of first hollow protrusion members and the plurality ofsecond hollow protrusion members have been formed and preparing thethrough type aluminum sheet by winding the through type aluminum sheeton the first roller after the metal oxidation layer is formed.
 9. Themethod of claim 8, wherein forming the plurality of first hollowprotrusion members and the plurality of second hollow protrusion memberscomprises: forming a plurality of through holes in the through typealuminum sheet by perforating the through type aluminum sheet byapplying pressure in the first surface or the second surface using oneof a cylindrical pillar member, an elliptical pillar member, and asquare pillar member each having a pointed tip, and integrally formingthe plurality of first hollow protrusion members or the plurality ofsecond hollow protrusion members so that the plurality of first hollowprotrusion members or the plurality of second hollow protrusion membersare extended and protruded from the through type aluminum sheet in sucha way as to respectively communicate with the plurality of throughholes.
 10. The method of claim 9, wherein each of the plurality of firsthollow protrusion members and the plurality of second hollow protrusionmembers is protruded to a first side or second side of the through typealuminum sheet.
 11. The method of claim 8, wherein in preparing thethrough type aluminum sheet by winding the through type aluminum sheeton the first roller, the metal oxidation layer is formed using ananodization method, and Al₂O₃ is used as materials for the metaloxidation layer formed by the anodization method.
 12. The method ofclaim 8, wherein in preparing the first active material sheet andpreparing the second active material sheet, the first active materialsheet and the second active material sheet are made of identical activematerials, and the active materials comprise an electrode substance of60 to 80 wt % and a viscosity control substance of 20 to 40 wt % andhave viscosity of 5000 to 10000 cps (centi Poise).
 13. The method ofclaim 12, wherein: the electrode substance comprises activated carbon of85 to 95 wt %, a conductive agent of 3 to 8 wt %, and a binder of 2 to 7wt %, the activated carbon is fabricated by performing activationprocessing on carbon particle powder fabricated using an aqueoussolution method, the activation processing is performed by mixing thecarbon particle powder and mixed alkali in a wt % ratio of 1:2 to 3,drying the mixture, and annealing the dried mixture in a tube furnaceunder a nitrogen atmosphere in a temperature of 600 to 1000° C., and themixed alkali is mixed so that a wt % ratio of NaOH and KOH is 1:9 to 12.14. The method of claim 12, wherein the viscosity control substancecomprises alcohol of 30 to 60 wt % and pure water of 40 to 70 wt %. 15.The method of claim 8, wherein simultaneously pressurizing the firstactive material sheet and the second active material sheet using thepress unit comprises: primarily pressurizing the first active materialsheet and the second active material sheet with first pressure using apair of first press rollers so that the first active material sheet andthe second active material sheet are respectively placed in the firstsurface and second surface of the through type aluminum sheet and bondedto the metal oxidation layer; and secondarily pressurizing the firstactive material sheet and the second active material sheetsimultaneously with second pressure higher than the first pressure usinga pair of second press rollers so that the primarily pressurized firstactive material sheet and second active material sheet are connectedthrough the plurality of first hollow protrusion members and theplurality of second hollow protrusion members, wherein the firstpressure is set by an interval between the pair of first press rollers,and the second pressure is set by an interval between the pair of secondpress rollers.
 16. The method of claim 15, wherein in secondarilypressurizing the first active material sheet and the second activematerial sheet, the second pressure is applied so that thicknesses ofthe first active material sheet and the second active material sheetbonded to the first surface and second surface of the through typealuminum sheet are 2 to 30% smaller than thicknesses of the first activematerial sheet and the second active material sheet bonded to the firstsurface and second surface of the through type aluminum sheet by thefirst pressure.